<template>
       <header class="header">
       <h1>小黑记事本</h1>
       <input v-model="todoName" @keyup.enter="add" placeholder="请输入任务" class="new-todo" />
       <button class="add" @click="add">添加任务</button>
     </header>
</template>

<script>
export default {
    data(){
        return {
            todoName:''
        }
    },
    methods:{
        add(){
            if (this.todoName.trim()==='') {
                alert("禁止为空")
                return
            }
            this.$emit('add',this.todoName),
            this.todoName= ''       
        }
    }
}
</script>

<style>

</style>